U.S. Pat. No. 7,391,067, issued Jun. 24, 2008 in the name of Kumar, describes temperature problems associated with the use of gallium arsenide (GaAs) substrates for fabrication of planar transistors for radio-frequency (RF) use. As noted by Kumar, the term RF encompasses more than the traditional radio frequencies.
High transmit power is desired in transmit-receive (TR or T/R) modules associated with radar antennas or sonar projectors. Having the highest possible power in each module tends to reduce the number of modules associated with each array, which is a cost advantage. The high power, long duty cycles, and high voltage experienced by GaAs power amplifiers, especially in view of their relatively poor thermal conductivity, tends to promote thermal runaway or thermal avalanche, which can destroy the device. These conditions are exacerbated by the close packing of the modules required by the dimensions of antenna or projector array elements.
Improved or alternative integrated circuits are desired.